1. Field of the Invention
The present invention relates to an electric actuator which makes it possible to allow a displacement member to perform rectilinear motion by converting rotary motion of a feed screw into rectilinear motion by using a feed nut.
2. Description of the Related Art
An electric actuator, which is based on the use of a feed screw, has been hitherto used as a means for transporting a workpiece or the like. Such an electric actuator includes the feed screw which is arranged at the inside of a frame and which is connected to a rotary shaft of a motor. A feed nut, which is provided for a displacement member, is engaged with the feed screw. The displacement member is formed with a protruding section which protrudes to the outside through a slit formed for the frame. A slider is provided on the protruding section.
When the motor is driven, the feed screw is rotated. The rotary motion is converted by the feed nut into the rectilinear motion to displace the displacement member. The slider is displaced integrally with the displacement member, and thus the workpiece, which is placed on the slider, is transported.
However, in the case of the electric actuator concerning the conventional technique described above, the load caused by the weight of the workpiece is applied to the feed screw via the displacement member and the feed nut. Therefore, when a heavy matter is transported, the following inconvenience arises. That is, the feed screw is bent by the load, and any trouble occurs in the displacement action of the displacement member. Further, the abrasion amounts of the feed screw and the feed nut are increased. As a result, a problem arises such that the service life of the electric actuator is shortened.
An object of the present invention is to provide an electric actuator which makes it possible to avoid any application of a load of a workpiece to a feed screw and smoothly transport the workpiece composed of a heavy matter.
According to the present invention, the load, which is applied by a workpiece, is absorbed by a guide mechanism provided at the outside of a frame. A feed screw is prevented from any application of the load. Accordingly, no problem occurs, which would be otherwise caused, for example, such that the abrasion amounts of the feed screw and a feed nut are increased. It is possible to smoothly transport the workpiece composed of a heavy matter.
In the present invention, the guide mechanism is provided detachably with respect to the frame and a slider. Accordingly, a convenience is obtained such that the guide mechanism can be exchanged, if necessary, without disassembling an entire electric actuator.
Further, in the present invention, a floating mechanism is provided, which enables the slider to displace in a direction in which the load is applied to a projection. Accordingly, it is possible to reliably avoid any application of the load of the workpiece to the displacement member. Further, it is possible to avoid any occurrence of looseness in the slider, and it is possible to stably transport the workpiece.